(a) Field of the Invention
The present invention relates to a hand tool aided screwdriver, and more particularly to a ratchet screwdriver allowing extra force to be jointly applied on a work piece from another hand tool such as a spanner by leverage.
(b) Description of the Prior Art
As taught in U.S. Pat. No. 6,260,446 for a ratchet screwdriver that permits application of extra force to drive a screw or a bolt in one direction or in a changed direction. However, as the force applied is limited only to that from the wrist of the user, more efforts are still needed for a job involving greater torque.